TDS Levels Research Articles

Treatment using reverse osmosis of an effluent from stainless steel manufacture

Reverse osmosis (RO) and physical/chemical technology were evaluated for treatment of neutralized spent acid effluent (seepage) containing high concentration levels of TDS (7500 mg/l), Ca (400 mg/l), Cr VI (42 mg/l), nitrate-nitrogen (827 mg/l), ammonia-nitrogen (33 mg/l), fluoride (13 mg/l), phenolics (45 mg/l) and COD (620 mg/l). The calcium concentration level in the seepage could be reduced from approximately 400 to 5 mg/l with soda ash softening. Initial permeate flux (feed and bleed system, 85% water recovery) was 278 l/m 2·d. Permeate flux, however, dropped rapidly in the beginning of the run and then remained approximately constant to the end of the run. However, chemical cleaning of the membranes was necessary to maintain flux. The TDS of the RO feed could be reduced in one case from 34,253 to 1560 mg/l (95.5% removal) at 85% water recovery. Nitrate and ammonia nitrogen were reduced from 2691 and 103 mg/l to 414 (84.6% removal) and 15 mg/l (85.3% removal), respectively. Chromium VI and fluoride were reduced from 183 and 90 mg/l to 0.38 (99.8% removal) and 2.8 mg/l (96.9% removal), respectively. COD removals varied between 60 and 80%. No phenolics, however, could be removed from the feed (approximately 32 mg/l) with the cellulose acetate RO membranes. Phenolics, however, could be effectively removed (<0.2 mg/l) from the RO permeate with hydrogen peroxide oxidation or ion-exchange treatment. Preliminary test work has shown that it should be possible to treat the seepage effectively with RO for pollution control, effluent volume reduction and water recovery. Capital costs for a 600 kl/d plant for lime softening, RO and oxidation equipment are estimated at U.S. $58,000, U.S. $350,000 and U.S. $87,500, respectively.

Groundwater treatment in the Central Region of Saudi Arabia

Groundwater is the main supply of water used in the Central Region of Saudi Arabia. With the exception of the capital city Riyadh, major cities in the region depend entirely on treated groundwater for drinking purposes. The groundwater of the region is characterized by high levels of TDS, with calcium, chloride, sodium, and sulfate being the dominant ions. Treatment of groundwater in three of the major cities of the region is accomplished in three reverse osmosis (RO) treatment plants. The capacity of these plants ranges from 8,700 to 51,000 m 3/d. The plants serve the cities of Unayzah, Al-Zulfi, and Al-Majmaah with a population of nearly 150,000. This paper intends to describe the RO water treatment plants in those three cities in terms of their operating process as well as performance. Information on ground and product water quality will be presented.

Lowering Kraft Black Liquor Viscosity by Ultrafiltration

Abstract High viscosity is a major factor limiting the percentage total dissolved solids (%TDS) to which kraft black liquor (KBL), a spent pulping liquor, can be concentrated before it is burned to recover its fuel value and its inorganic chemicals. The effect on black liquor viscosity of removing high molecular weight lignin by ultrafiltration of 16% and 24% TDS liquors was studied. Viscosities of ultrafiltration permeates were reduced relative to feed black liquors. When a permeate was concentrated to higher %TDS levels, its viscosity decreased yet further relative to feed samples evaporated to similar solids levels. Retentate viscosity was very high relative to both feed and permeate. Ultrafiltration was carried out at 75[ddot]C using polysulfone membranes in a plate-and-frame or hollow fiber system. Flux rates varied greatly depending upon the specific liquor used. Flux was enhanced by increased temperature and increased linear velocity. The membrane molecular weight cutoff (MWCO) typically used was 5...

Optimizing design and cost of seawater reverse osmosis systems

The influence of design parameters, such as raw water temperature and total dissolved solids content (TDS), design pressure, and recovery, on total unit cost for the production of desalinated water from the Arabian Gulf in Saudi Arabia by means of reverse osmosis is presented for plant capacities ranging from 75,000 m 3/d to 700,000 m 3/d. It is concluded that total unit water cost is significantly influenced by raw water TDS, design pressure and design recovery. It is recommended to investigate the feasibility of operation at increased pressure. Finally, total water costs for reverse osmosis desalination are presented also as a function of salinity, with TDS levels ranging from 3000 mg/l to 55,000 mg/l.

Comparative Limnology and Biota of Mine Spoils Ponds in Colorado

Physico-chemical and biotic parameters were investigated from June 1977 to May 1978 in coal strip-mine ponds in Colorado which differed in age and in the proportion of drain- age derived from the mine. There were no discernible effects of mine drainage on temperature, dissolved oxygen, hardness, pH, acidity, alkalinity, calcium, iron, orthophosphate, or the organic content of the substrate. In contrast to spoils ponds in eastern and midwestern states, acid mine drainage was not observed. Total dissolved solids, nitrate, and sulfate values were higher in the spoils ponds than in the control pond. Net zooplankton abundance was lowest in the youngest spoils pond, but the standing crop of benthos exhibited a progressive decrease from the youngest spoils pond to the control pond. Certain zooplanktonic and benthic species were rare or absent in the youngest spoils pond. Colonization phenomena (age and distance from a source of colonizers) are postulated as responsible, in part, for the faunal differences between ponds, although higher levels of nitrate, sulfate, and TDS in the spoils ponds may provide adverse conditions for certain species. If these data are typical of the western energy region, they suggest the potential for devel- opment of recreational lakes as a part of reclamation practices.

River basin salinity management via the ASTRAN method: II. Case study

The accelerated salt transport ( astran) method for managing salinity in an irrigated stream-aquifer system is applied to the lower San Luis Rey River basin in southern California. The hierarchical management algorithm developed in Part I is applied for optimally implementing astran over the basin. Three subbasins are included in the study; Pauma, Pala and Bonsall. Unsaturated and saturated zone models for water quantity and quality are calibrated for the area, including important ions such as Ca 2+, Mg 2+ and Na + as well as SAR. Once the models have been satisfactorily calibrated, a 20-yr. planning period is selected which is divided into two 10-yr. model periods. Hydrologic, land-use, water-demand and water-supply projections are then made for each subbasin. The hierarchical algorithm is then applied, which results in a set of policies over a range of possible levels of total available imported water. For the same quantity of imported water, astran reduces the degradation rate by about one-fifth of what is projected under normal irrigation practice (called the no-management case). astran appears to perform best when the groundwater is allowed to degrade to higher, yet still usable, TDS levels.

Comparison of Potentiodynamically Determined Pitting Rates with Actual Pitting Rates for Mild Steel and Admiralty Brass in Oxygen Bearing Waters

Abstract Pitting rates of mild steel and admiralty brass, determined microscopically are compared with those obtained potentiodynamically for both laboratory and field tests. The comparisons clearly demonstrate that the potentiodynamic method is a viable means for measuring the pitting rates of the systems studied. Solution resistance effects for TDS levels below 452 ppm greatly overshadow the rates obtained potentiodynamically. Consequently, special electrode configurations need be utilized in order to obtain meaningful results for these lower TDS solutions.